The present invention relates to an airbag and an airbag apparatus in which the airbag is expanded in a manner such that, at least one part of a face of the airbag facing an occupant has a shape caved from a peripheral portion of the airbag in a direction to be spaced from the occupant. More particularly, the invention relates to an airbag and an airbag apparatus that is preferably used with a driver-side seat.
An airbag apparatus for use in a driver-seat of a motor vehicle is provided with an airbag, a retainer that holds the airbag on a steering wheel, a gas generator that expands the airbag, and a module cover that is attached to the retainer in a manner so as to cover the airbag being folded. In the event of a crash of the motor vehicle, the airbag pushes open the module cover and is expanded to a front face side of the steering wheel (to a side of an occupant seated on a driver-side seat), and protects the occupant seated on the driver-side seat.
In U.S. Pat. No. 6,695,344, an airbag apparatus is described, in which a center portion of a face of the airbag, when expanded, facing the occupant is formed to be a concave portion caved from a peripheral portion of the airbag in a direction to be spaced from the occupant. In the airbag apparatus of U.S. Pat. No. 6,695,344, a center portion of the face of the airbag facing the occupant is fixed to the retainer by a center portion of the module cover (or by a fixing member disposed at the center portion of the module cover).
Further, in the airbag apparatus of U.S. Pat. No. 6,695,344, the module cover is disunited between the center portion thereof and a peripheral portion thereof, when the airbag is expanded, and only the peripheral portion of the module cover is brought to be opened. At that time, the center portion of the module cover remains at a front face of the retainer and the center portion of the face of the airbag facing the occupant is pressed to the retainer by the center portion of the module cover or the fixing member.
In the airbag apparatus in U.S. Pat. No. 6,695,344, because an expansion amount of the airbag to an occupant side of a center portion of a face of the airbag facing the occupant is limited, the airbag is prevented from being expanded to the occupant side thereof in a rapidly protruding manner. In addition, the airbag is thereby accelerated to be expanded in a lateral direction (radial direction) of the airbag and the airbag is immediately extended to a wide area. Further, volume of this airbag is made smaller to the extent of the shape of the airbag, which is caved at a center portion of the face of the airbag facing the occupant in the manner described above. Accordingly, the airbag can be immediately expanded even when a gas generator having relatively low output is employed.
In the airbag apparatus disclosed in U.S. Pat. No. 6,695,344, there is a possibility that a body of an occupant intrudes into a concave portion at a face of the airbag facing the occupant, when the airbag is expanded. In this case, a peripheral portion of the concave portion is deformed in a manner such that the same buckles by compression in a direction to open the concave portion and, as a result, there is a possibility that the body of the occupant is not firmly caught.
In the airbag apparatus disclosed in U.S. Pat. No. 6,695,344, because the center portion of the face of the airbag facing the occupant is fixed to a retainer by the center portion of a module cover or by a fixing member disposed at the center portion of the module cover, the configuration of the airbag apparatus becomes complicated and assembly work for the airbag apparatus becomes bothersome, resulting in a high manufacturing cost. In addition, because of the increased number of parts, the weight of the airbag apparatus becomes great.
Accordingly, it is an object of the present invention to provide an airbag having high protection characteristics even though at least one part of a face of the airbag facing an occupant has a concave portion caved in a direction to be spaced from the occupant.
It is another object of the present invention to provide an airbag apparatus provided with the aforementioned airbag according to the invention.
In addition, it is another object of the present invention to provide an airbag and an airbag apparatus having a simple configuration.
Further objects and advantages of the invention will be apparent from the following description of the invention and the associated drawings.